Background. Kratom is a drug derived from the leaves of the tree Mitragyna speciose, which is native to southern Thailand. The route of administration is oral. Kratom has become increasingly available in the United States. The active ingredients in the drug bind the opioid mu-receptor; therefore, kratom has similar physiological effects as mu-opioids. Elevated prolactin is a common medical condition frequently caused by a variety drugs, including opioids.

Case Report. A 42-year-old man presented with poor energy and low libido. He had mildly elevated serum prolactin with hypogonadotropic hypogonadism as evidenced by low serum testosterone with luteinizing hormone and follicle-stimulating hormone in the normal range. At his initial visit, he reported no use of any recreational or therapeutic drug. Two months later when seen in follow-up, both the testosterone and prolactin levels had returned to normal. At that visit he reported frequent use of kratom, which he had discontinued a few days after the first visit.

Discussion. Kratom is now widely available in health food stores and online and is considered an emerging drug of abuse. At present kratom is legal in the United States, but recently the Drug Enforcement Administration served noticed of its intention of making kratom a Schedule I drug. A number of adverse events or side effects have been reported, but this is the first report of hyperprolactinemia as the result of ingestion of kratom.

Ethnopharmacological relevance - Mitragyna speciosa (Korth.) also known as kratom, is a native medicinal plant of Southeast Asia with opioid-like effects. Kratom tea/juice have been traditionally used as a folk remedy and for controlling opiate withdrawal in Malaysia. Long-term opioid use is associated with depletion in testosterone levels.

Aim of the study - Since kratom is reported to deform sperm morphology and reduce sperm motility, we aimed to clinically investigate the testosterone levels following long-term kratom tea/juice use in regular kratom users.

Methods - A total of 19 regular kratom users were recruited for this cross-sectional study. A full-blood test was conducted including determination of testosterone level, follicle stimulating hormone (FSH) and luteinizing hormone (LH) profile, as well as hematological and biochemical parameters of participants.

Results - We found long-term kratom tea/juice consumption with a daily mitragynine dose of 76.23 mg to 94.15 mg did not impair testosterone levels, or gonadotrophins, hematological and biochemical parameters in regular kratom users.

I have several kilos of a variety of Kratom but never use the stuff. White vein was my favorite for pain relief but the taste was just hard to swallow. If I capped them I could probably use it more often but never got around to it.